1. Field of the Invention
The invention relates to a method for manufacturing an image sensor, and in particular to a method capable of manufacturing an image sensor having fewer particles on a photosensitive chip or a transparent layer and having improved quality.
2. Description of the Related Art
A general sensor is used to sense signals, which may be optical or audio signals. The sensor of the invention is used to receive image signals or optical signals. After receiving the image signals, the sensor converts the image signals into electrical signals, which are then transmitted to a printed circuit board via a substrate.
Referring to FIG. 1, a conventional image sensor includes a substrate 10, a frame layer 18, a photosensitive chip 26, a plurality of wires 28, and a transparent layer 34. The substrate 10 has an upper surface 12 on which first connection points 15 are formed, and a lower surface 14 on which second connection points 16 are formed. The frame layer 18 has a first surface 20 and a second surface 22 adhered to the upper surface 12 of the substrate 10 to form a cavity 24 together with the substrate 10. The photosensitive chip 26 is arranged within the cavity 24 and is mounted to the upper surface 12 of the substrate 10. Each wire 28 has a first terminal 30 and a second terminal 32. The first terminals 30 are electrically connected to the photosensitive chip 26, and the second terminals 32 are electrically connected to the first connection points 15 of the substrate 10. The transparent layer 34 is adhered to the first surface 20 of the frame layer 18.
In the image sensor, however, even if the transparent layer 34 and the photosensitive chip 26 are cleaned before the packaging process, some particles may be attracted to the transparent layer 34 and the photosensitive chip 26 owing to electrostatic charges, and the image sensor quality may be influenced accordingly.
An object of the invention is to provide a method for packaging an image sensor capable of eliminating electrostatic charges within the image sensor and preventing particles from being attracted to the photosensitive chip.
Another object of the invention is to provide a method for manufacturing an image sensor capable of adhering particles to an adhesive layer without influencing the image sensor quality.
To achieve the above-mentioned objects, the invention provides a method for manufacturing an image sensor including the steps of: providing a substrate having an upper surface and a lower surface; mounting a frame layer to the upper surface of the substrate to form a cavity together with the substrate; mounting a photosensitive chip to the upper surface of the substrate and within the cavity; providing a plurality of wires to electrically connect the photosensitive chip to the substrate; supplying an adhesive layer to the upper surface of the substrate and within the cavity; mounting a transparent layer to the frame layer to cover the photosensitive chip; and illuminating an electrostatic-charge eliminating light source on the transparent layer to let particles within the cavity fall down to the adhesive layer.
Consequently, the particles may fall down to the adhesive layer, and it is possible to prevent the particles from being attracted to the photosensitive chip or the transparent layer and to prevent the particles from influencing the image sensor quality.